python学习 2019-2-19

一，名词:
根 边 树叶（叶子） 兄弟 祖父和孙子 路径 路径的长 深度 高
祖先 后裔 真祖先 真后裔
二，树的实现
class TreeNode():
def init(self,data,firstchild,nextSibling):
self.data = data
self.firstchild = firstchild
self.nextSibling = nextSibling
三，树的遍历
深度优先
广度优先

四，二叉树
最多两个孩子
五，二叉查找树（搜索树）
添加
遍历（深度优先）
递归

#树的实现
class TreeNode():
    def __init__(self,data,firstchild,nextSibling):
        self.data = data
        self.firstchild = firstchild
        self.nextSlibling = nextSibling


class TreeNode():
    def __init__(self,data,left = None,right = None):
        self.data = data
        self.left = left
        self.right = right
class Tree():
    def __init__(self):
        self.root = None
    #添加数据
    def add(self,data):
        node = TreeNode(data)
        if self.root == None:
            self.root = node
        else:
            currentNode = self.root
            while True:
                if data<currentNode.data:
                    if currentNode.left == None:
                        currentNode.left = node
                        break
                    else:
                        currentNode = currentNode.left
                        continue
                else:
                    if currentNode.right == None:
                        currentNode.right = node
                        break
                    else:
                        currentNode = currentNode.right
                        continue
        #判断是否包含数据
    def contains(self,data):
        flag = False
        if self.root == None:
            print("空树！！！")
        else:
            currentNode = self.root
            while True:
                if currentNode.data == data:
                    flag = True
                    break
                else:
                    if data < currentNode.data:
                        if currentNode.left == None:
                            break
                        currentNode = currentNode.left
                    else:
                        if currentNode.right == None:
                            break
                        currentNode = currentNode.rigt
        return flag
#查找最小值
    def findMin(self):
        temp_min = None
        if self.root == None:
            print("空树！！！")
        else:
            currentNode = self.root
            while currentNode.left != None:
                currentNode = currentNode.left
                temp_min = currentNode.data
        return temp_min
    #查找最大值
    def findMax(self):
        temp_max = None
        if self.root == None:
            print("空树")
        else:
            currentNode = self.root
            while currentNode.right != None:
                currentNode = currentNode.right
                temp_max = currentNode.data
        return temp_max
    #删除
    def remove(self,root,data):
        if self.contains(data):
            pre_currentNode = None
            currentNode = root
            while True:
                if currentNode.data == data:
                    #叶子节点
                    if currentNode.left == None and currentNode.right == None:
                        del currentNode
                        break
                    #一个孩子节点
                    elif currentNode.left == None and currentNode.right != None:
                        if pre_currentNode == None:
                            self.root = currentNode.right
                            break
                        else:
                            if pre_currentNode.right == currentNode:
                                pre_currentNode.right = currentNode.right
                            else:
                                pre_currentNode.left = currentNode.right
                                break
                    elif currentNode.left != None and currentNode.right == None:
                        if pre_currentNode == None:
                            self.root = currentNode.left
                            break
                        else:
                            if pre_currentNode.right == currentNode:
                                pre_currentNode.right = currentNode.left
                            else:
                                pre_currentNode.left = currentNode.left
                            break
                    #两个孩子节点
                    else:
                        minNode = currentNode.right
                        while minNode.left != None:
                            minNode = minNode.left
                        currentNode.data = minNode.data
                        self.remove(currentNode.right,minNode.data)
                        break
                else:
                    if data < currentNode.data:
                        pre_currentNode = currentNode
                        currentNode = currentNode.left
                    else:
                        pre_currentNode = currentNode
                        currentNode = currentNode.right
        #树中没有数据
        else:
            print("数据不存在")
    #查找（深度优先）
    def showAll(self,root):
        if root ==None:
            print("空树")
        else:
            if self.root.data == root.data:
                print(self.root.data)
            if root.left != None:
                print(root.left.data)
                self.showAll(root.left)
            if root.right != None:
                print(root.right.data)
                self.showAll(root.right)
tree = Tree()
tree.add(6)
tree.add(2)
tree.add(8)
tree.add(1)
tree.add(5)
tree.add(3)
tree.add(4)
tree.remove(tree.root,2)
tree.showAll(tree.root)